package com.itheima.filter;


import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebFilter(value = {"/addStudent.jsp","/listStudent.jsp"})
public class LoginFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
       //转换参数类型
        HttpServletRequest request= (HttpServletRequest) servletRequest;
        HttpServletResponse response= (HttpServletResponse) servletResponse;
       //获取会话域中的数据
        Object username = request.getSession().getAttribute("username");
//判断用户名
        if (username==null||"".equals(username)){
            //重定向到登录界面
            response.sendRedirect(request.getContextPath()+"/login.jsp");
            return;
        }
        filterChain.doFilter(request,response);
    }
}
